EMI Gaskets try to achieve two things:
- They try to shield electronics from EMI/RFI waves that are inherent in our daily lives now, OR conduct electricity in a certain direction to avoid electrostatic discharge to the wrong places. Sometimes they do both.
- They serve as environmental seals/gaskets. Each EMI Shielding product varies in how well, and what it seals against. For example, most EMI gaskets are made of silicone, thus being good at sealing in high temperature environments. As another example, fluorosilicone is used in fuel laden applications.
One thing most EMI/RFI shielding products are not good at, is avoiding extrusion under pressure. In fact, I view most EMI/RFI shielding products are fairly weak, and wouldn’t recommend a compression value of more than 25% on any flat gasket- and there should be compression stops. I’ve seen way too many EMI/RFI shielding products extrude under improper pressure, or compression. With that said, I thought I’d list out some products that can be used in high pressure applications for EMI/RFI Shielding.
Product Selection for Reinforced EMI/RFI Shielding
1. Fabric/Mesh Reinforced EMI/RFI Shielding Products
Specialty Silicone Products is a company located in New York. They have some unique products. They have a variety of Fabric Reinforced Silicone Products
-SSP-502-65-020 Nickel/Graphite, 65A Durometer with Conductive Fabric, .020’’ Thick– datasheet download
-SSP-502-65-032 Nickel/Graphite, 65A Durometer with Nickel-Coated Mesh, .032’’ Thick– datasheet download
2. Wire Oriented Fluorosilicone/Silicone Products
These materials are offered by a number of manufacturers. These products have thousands of wires oriented perpendicular to the elastomer. Wire Oriented EMI Products do two things:
A. The wires make electrical contact with the said surfaces.
B. The wires also offer additional reinforcement that prevent the gasket from being squeezed too hard and extruding.
3. Expanded Wire EMI Shielding Products
These materials are offered in a variety of fluorosilicone/silicone/neoprene products along with other wire materials. These are usually much thinner profiles than the previous two materials. Offered in thicknesses .016’’ , .020’’ .